I have a 1994 k3500 , pretty much stock just your basic up grades nothing Proformace yet. But the problem I'm running into is when I start up truck mostly the first initial start. I have a lot of smoke white smoke an kinda a rough I kinda have a guy feeling it's injector pump ?? Not sure

1994 k3500 4x4 with 33in M/T tires , muffler delete.

 

Sounds more like you need new bosch glow plugs and/or injectors rebuilt/replaced?
As long as it's not eating coolant.

 

I've replaced the glow plugs , but there AC/delco

 

Check each glow plug wire to make sure that they all get power-there are fusible links for each plug as well as each bank of plugs.